Hydraulic ratio drive



Jan- 1951 H. B. MCDONALD 2,536,200

HYDRAULIC RATIO DRIVE Filed Aug. 1:5, 194? 5 Sheets-Sheet l Jan. 2, 1951MCDONALD 2,536,200'

HYDRAULIC RATIO DRIVE Filed Aug. 15, 1947 5 Sheets-Sheet 2 flazycma Z62H. B. M DONALD HYDRAULIC RATIO DRIVE Jan. 2, 1951 5 Sheets-Sheet 5 FiledAug. 15, 1947 Patented Jan. 2; 1951 UNI TE D STATES PAT F ICE! HYDRAULICRATIODRIYE Harrison=-B.- McDonald; Abilene, Tex.

Application August-13, 1947, Serial Newcastle 3:Cla ims.'- (01. 103-126)This invention relates. to an improved hydraulic transmission and moreparticularly to a hydraulic transmission having means for varying thespeed ratio-of the driving and driven shafts.

It is an object ofthis invention to" provide an improved hydraulictransmission of the kind to be more particularly described'hereinafterhaving a hydraulic pump driven by the drive shaft; anda driven-shaftfixed on the pump casing, and. having a hydraulic.circuit-betweentheiniet and discharge ports" of the pump-with a valve for varying theflow throughout" the circuit-for varying the speedrelationof' thedriving-and driven shafts:-

Another object "of-this invention is toprovide a hydraulic transmissionof this kind having an external connection whereby said transmission maybe used asapump forsupplyin pressure to an external fluidpressure'operated'devicm A- further object of 'this-invention is-to provide avhydraulic transmission of this kind having-a.

housing which constitutes areservoir forthe hydraulic fluid and in whichthe driving and driven shafts. are connected together by afiuid. clutchv formed hy'a hydraulic pumpicarriecl partlybyw thedrivenshaftand partlyby the .drivingshait. A valveis disposed between -thecinlet and outlet;ports .of. the pumpqand. the "p.0sition...of.. theavalve:determinasitherflowzof fluid. from the. discharge.

port tothe' inlet .port, the solidity of the. connec: tion beingdetermined and controlledby the potsition of the valve and the flow ofhydraulic. fluid. r

A still further. objectof this. invention is. to provide. a. hydraulic;transmission of. this kind having a fluid connection betweenthe-driving.-

and. driven shafts so constructed and. arran ed whereby the drivingconnection will bedependent upon. and inverselyproportional, to.theflow: of fluid. Whenthe valve. is opened topermit. thefree flow offluid through the pump and its. associated conduits.vboth,shafts...wil1. be inde-.- pendent and as the newts-restrictedtherotation of the pump gearswill be restrictedefiecting rotation of thedriven shaft .by the. drive shaft. Yet another. object of thisinventionis .to provide a pressure. relief valvev in a hydraulic transmission of this; kindwhich may be setto open. at, a predeterminedpressure to. prevent therupsture. of any of the. parts of. thetransmissiondue to an excessive pressure in thesystem, caused bystopping of the driven shaft.

With the above and other, objects-inviewrmy invention consists'izrthearrangement, combina-v tion and details of 'iconstruction disclosed inthe. drawings and specification; and then more par ticularlypointedoutflin the appended claims.

Inthe drawings,

Figure .a longitudinalsection of'a hydraulic transmission constructedaccording to an, embodiment of my invention,

Figure,2"'is' a horizontal? section taken on line. 2'1-2 of-Figure 1;

Figure 3 is a vertical:section;taken ,on theline; 3--3 of Figure I,

Figure 4 is a vertical, section. partly broken" away taken onthe.line.4*-4' of, Figure '1;

Figure 5 isa vertical section takenonthedinev 5'5"of '-Figurer1;

Figure 6 is; asectiontaken on the line Ge-Qof Figure 1,

Figure 7 is a i.ragmentary detail;horizontalsection taken on the linel-'l'"of Figure 3; and? Figure 8 is a fragmentary horizontal sectiontaken on theline 8 -8.of.Fignre 1.

Referring to the drawings; the numeral" iflf'designates generally thehousing for a.hydraulic. transmission inwhich the connection between;the driving. andj'the driven shaftiis efiectedi'by the;

- therate' of flow-of hydraulic; fluid between the.

connecting; membersicarried by; the, shafts: A drivingshaftgasr Hisrotatahly supportedfat one end of the housing ['0 and the drivenvshaft a l2 isrotatably supported. inv theihousing Hi" at the other end.of 'thehousing from the shaft, being substantially;coeaxial" with the:driving; shaft ll; v Y

The. shafts I l 'andTIZIare; provided! with splines;

l4 ontheir outer end" which extend'from the housing H forattachmentofthe shaftsgl f" and;

I2"to the-motive power. shafts andto the shaft ofthe driven element;

The: housing :I i] is .hollow and provides va-reservoirfor the fluid. inthe..connecting means be;- tween the driving and driven shafts. A fluid:

connection whichincludes a; hydraulic pump, I5}.

tatably j'ournalled; Thehousinglt is formed of;

a central disc member I9'providedwith annular interengagingopenings and2! withinwhich the gears llandilkare engaged.

The teeth 22 ofthe-gears ITand' IBare spaced,"v

from the walls: of thegannular. openings-.211v and 21" sufiicient' only.for-the rotation. of the.- gears, in these openingsi. 'I'liel gear I1 iselongatedij providing substantially a cylindrical member having bearingbosses 24 on each end thereof. The bosses 24 are journalled in bearings25 carried in or fixed in their outer plates 26 and 21 of the pump |5.

The end plate 26 of the pump I5 is provided with an outwardly extendingconcentric boss or bearing 28 which is rotatably supported in a standard29 fixed in the housing In. Bearings 3!! are provided betweenthestandard 29 and the bearing box 28 for free rotation of the member 28 inthe standard 29.

The gear i8 is of a suitable configuration for closely engaging with theteeth of the gear H. The driving shaft extends through the bearingmember 28 and through the central member l3 of the pump l5 and isjournalled at its inner end in a bearing 3| carried by the end plate 21.,The gear I8 is fixed on the driving shaft H by a key 32 or othersuitable fastening means whereby the gear I3 is rotated directly by therotation of the driving shaft l. The driven shaft |2 is fixed to thepump |5 by direct connection with the end plate 21 thereof. A connectingmember 34' is fixed to vor formed on the driven shaft |2 within thehousing l and the member 34 is formed with an' annular. flange 35 at itsinner end which is adapted to be secured to the end plate 2? by bolts 35or other suitable fastening devices.

The connecting member 34 is provided at its outermost end with a reduceddiameter bearing surface 31 engaging in a, bearing 33 supported on astandard 39 fixed in the housing Ill.

Fluid conducting means through which the hydraulic fluid is adapted toflow upon operation of the gears of the pump is carried by and formed inthe connecting member 34. The'end plate 21 of the pump I is providedwith a" pair of spaced apart openings 48 and 4| through'wh'ich the'fluidmay flow in its passage through thepump I5 and the gears l1 and l8.

' The'openings 40 and 4|. of the end plate 2'! communicate directly onone side with openings 42 and 44' respectively which are formed in thecentral member N3 of the pump |5 adjacent the gears H and H3 at thepoint of engagement the'rebetween. 5

Asshown in'the drawings; the openings 40 and 42 provide an inlet portfor the pump l5 and the openings 4| and 44 provide an outlet port. Theconnecting member 34 which is carried by the driven shaft I2 is providedwith a series of longitudinally extending drilled passages or openings45 which communicate at one end with the arm ate slot or opening 40' ofthe end plate 27.

The passages 45 are circumferentially spaced apart about the peripheryof the member 34 on one side thereof. Drilled passages or openings 46are provided in the member 34 extending longitudinally thereoffor'communication with the outlet port or opening 4| of the endplate'21.

The openings or passages 46 are similar to the openings 45 beingcircumferentially spaced apart on one side of the member 34. Asealingmember or washer 43 is carried by the pump l5, between the end plate 21and the central portion of the housing l9. The sealing member 43 isformed with openings 41 and 48 therethrough between the openings 4| and44 and between the openings 42 and 4B of the adjacent pump parts.

Radially extending openings 49 are formed in the member 34' fromthe endsof the drilled passages'45 and the openings 49 provide passages aboutthe periphery of the member 34 throughwhich the hydraulic fluid isadapted to pass for its passage into the openings 45 and into the pumpI5. Drilled passages 55 are formed in the member 34 radially thereof forcommunication with the outer end of the passages 45 providing a fluidoutlet from the pump through the passages 46 and through the member 34.

The openings 49 and 58 are spaced apart longitudinally relative to theaxis of the member 34'. A bearing member 5| is provided for the member34 through which the fluid may be admitted to the passages 45 and 45 to.the pump H3. The bearing member 5| is formed of a tubular body 52 havinga pair of radial recesses or grooves 54 and 55 formed on the innersurface thereof. The recesses 54 and 55 are longitudinally spaced apartalong the length of the bearing 5|.

Sealing rings as 56 are carried by the bearing member 5| on theinner'surface thereof adjacent the ports or recesses 54 and 55 forengagement with the bearing or member 34. The recess 54 is disposedabout the bearing 34 for communication with the openings 49 in themember 34. The openings which open out of the bearing 34 communicatewith the passage or recess 54 of the bearing member 5|. A pipe ortubular connection 5? extends downwardly from the bearing 5| incommunication with the recess 54 therein. A similar pipe or tube 58extends downwardly from the bearing 5| and is in communication with therecess therein. 7

The pipes or tubes 5? and 58 extend down wardly and terminate a shortdistance above the bottom 59 of the housing Hi. The tubes 51 and 58provide the inlet and discharge openings or" the pump i5 in connectionwith the reservoir or fluid carried Within the housing It).

A connecting tube or pipe to is fixed between the tubes 57 and 58 belowthe bearing 5| within the housing In. A valve 51 is nxed along thelength of the connecting tube 55 for controlling the now of liquidthereoetween.

A check valve 52 which includes a ball 64 is carried by the lower end ofthe pipe 5? to permit the flow of liquid from the reservoir up into pumpi5. A snnilar check valve 65 having a housing 55 threadably mounted onthe lower end I of tne tube 58 and naving a ball check 5: permits thenow of fluid upwardly into the tube 58 and into th pump l5 upon reverserotation of the pump.

A pressure relief valve 68 is carried by the pipe 58 I01 use inrelieving the pressure when the pipe 58 is used as a discharge or outletpipe of the valve 55 closes a valve seat i i-formed bythe lower end ofthe valve 68.

For actuating the valve 5| between the tubes orpipes 5'1 and 58 a gear15 is nxed on the upper error or the valve stem thereof and a screw inis supported for engagement with the gear 11 5. The screw la is fixed onthe inner end or a shaft Tl which extends through one side-wall of thehous- A handle 18 is fixed on the outer end of the shaft 11 so thatrotation of the shaft will effect rotation'of.s the gearancriathe'gresultant closing onopening'of'thevalve6i; :'In the use andoperation ofz this; hydrauc; transmission described above, the. Vdriv-ing,.; haft t I is: connected to,v a suitable source of power;-supply as, an electricmotorzor.thelike; With the:

valve El in the full open .position;;for;permitting;

the free. flow, of the liquid-,causedto flow-1hr tn and through thepassages 46iand 50 into -the;=.

recess- 55 through the pip,e:.a5 azand Evalve thecycle is repeated.

1; If ,there, isv insufiicient fluid within thei-circuit of the pump,.the low. pressurel-"caused by the engagement of the rotating gearsa [1and [8' .will draw whatever, fluidnisfurther necessary-up through thecheck valve 64. Any excess fluid or pressure developed by the rotationof the pump I 5 will be discharged through the pressure relief valve 68.It will be seen then that with any friction or force restraining themovement of the driven shaft I2 when the valve BI is open the shaft IIwill rotate freely and the gears l1 and I8 will rotate freely within thepump l5 so that no torsional force will be transmitted from the drivingshaft II to the driven shaft l2. As the valve 6| is closed the flow offluid through the pump and connecting passages will be restricted orcompletely shut off so that the fluid will not pass freely through thepassages thereby restraining the free movement of the gear I! in thepump.

Since the gear I! will be locked against rotation as the driving shaftII is rotated, the torsional force exerted on this shaft will betransmitted through the gears 18 and I! to exert a torsional force onthe housing of the pump 15.

As the pump is directly connected to the driven shaft [2 this force ofthe driving shaft will be transmitted directly to the driven shaft forrotation therewith.

In the connected position of the transmission with the valve 6! closed alarge pressure will be set up in the discharge pipes and passages of thepump and this pressure may be regulated by the pressure relief valve 68so that the pressure may be relieved prior to the breaking of any of theconnecting parts between the shafts II and I2.

With the valve 6| partially open, a partially clutched condition willprevail between the shafts II and I2. In this manner the transmissionincluding the pump 15 and valve 6| will form a clutch which willmaintain the shafts H and I2 in engagement for a definite force orrestraining force on the shaft l2.

With a transmission of this kind, no other clutch members or devicesneed be provided and the valve 6! may be controlled or operated by anysuitable means by the operator of the vehicle equipped with such atransmission so that a full range or clutching engagement between theshafts II and [2 may be maintained.

A transmission of this kind may also be used with tractors and otherequipment in which it is desired to utilize the actual pump effect ofthe gears l1 and [8. As many accessory devices are 61 wherecarriedrbyqtractors; and; the: like I to be: operated by a. hydraulic;pumpi I. have'provided anioutletq videdwith a cap 8 6 forclosingthis-pipe whenit-is:-

not ,in. user, For ,usingthentransmissions I0 fast-a pump, the; valve 8|opened so; that-rotation otthe shaft-H will effect the rotation of,thegears.

t1 andrl8yfor pumpingthefluid throughthedis-e charge v pipev 58 and. Vout through the. accessory While: no return .,pipe1-is:. shownfrom.theaccessoryfluid drives since most, ofthe accessory drivesarepistonswhich require:

driverconnection. 80.

fluid, pressure in only one direction, no return fluid connectionwillberequired in manyin-VY- stances and where itis requireda suitable return:

connection may, be. madeto the, reservoir 01?:

housing and if desired may be connected to the pipe 57 with a suitablevalve connection. In the other or closed position of valve 8|, the fluidis discharged through the outlet 51 into the reservoir.

I do not mean to confine myself to the exact details of constructionherein disclosed, but claim all variations falling within the purview ofthe appended claims.

Having thus described my invention, what I claim is:

1. An improved hydraulic transmission comprising a reservoir containinghydraulic fluid, a pump housing rotatably mounted in said reservoir, aconnecting member secured to said housing for rotation therewith, adriven shaft secured to said connecting member, a drive shaft extendinginto said housing, a gear on said shaft, a sec- 0nd gear in said housingin mesh with said first mentioned gear, a hydraulic fluid inlet to saidhousing adjacent the point of engagement of said gears, a fluid outleton th opposite side of said gears relative to said housing,'a bearingmember having a pair of annular channels therethrough surrounding saidconnecting member, means communicating said inlet with one of saidchannels, means commumcating said outlet with the other= of saidchannels, tubes extending below the level of the fluid in said reservoircommunicating with each of said channels, inwardly opening check valvesin th lower ends of each of said tubes below the level of said nuid, aconnection between said tubes and a manually controlled valve in saidconnection.

2. An improved hydraulic transmission comprising a reservoir containinghydraulic fluid, a pump housing rotatabiy mounted in said reservoir, aconnecting member secured to said housing for rotation therewith, adriven shaft secured to said connecting member, a drive shaft extendinginto said housing, a gear on said shaft, a second gear in said housingin mesh with said first mentioned gear, a hydraulic fluid inlet to saidhousing adjacent the point on engagement of said gears, a fluid outleton the opposite side of said gears relative to said housing, a bearingmember having a pair of annular channels therethrough surrounding saidconnecting member, means communicating said inlet with one of saidchannels, means communicating said outlet with the other of saidchannels, tubes extending below the level of the fiuid in said reservoircommunicating with each of said channels, inwardly opening check valvesin the lower ends of each of said tubes below the level of said fluid, aconnection between said tubes, a manually controlled valve in saidconnection, and a pressure relief valve in one of said tubes.

- 3. An improved hydraulic transmissioncomprising a reservoir containinghydraulic fluid, a pump housing-rotatably mounted in said reservoir, aconnecting member secured to said housing' for rotation therewith, adriven shaft secured to said connecting member, a drive shaft extend--ing into said housing', a gear on said shaft, a second gearinsaid-housing in mesh with said-first mentioned gear, a hydraulic fluidinlet to said housing adjacent the point on engagement of said gears, afluid outlet on-the opposite'side of said gears relative to saidhousing,- a bearing member having a pair of annular channelstherethrough surrounding said connecting member,

means communicating said inlet with one of said channels, meanscommunicating said outlet withthe other of said channels, tubesextending below the level of the fluid in said reservoir com municatingwith each of said channels, inwardly opening check valves in the lowerends of each of said tubes below the level of said fluid, a connectionbetween said tubes, a manually controlled valve in said connection, apressure relief valve in one of 'saidtubes, an accessory driveconnection pipe communicating with one of said tubes, and a valve insaid pipe.

HARRISONB. MCDONALD.

; REFERENCES CITED The'following references are of-record in the DoranApr. 23, 1946

